As shown in FIG. 1, the general chain includes plural inner link plates 1 and outer link plates 2 which are corresponding to each other. The outer link plates 2 are attached to the outer surfaces of the inner link plates 1, and a pin 3 penetrates through a bushing 4 between two outer link plates 2 and two inner link plates 1 with two ends exposed out of the outer sides of the two outer link plates 2. Here, one end of the pin 3 has a bolt head 5, and the other end also should be riveted after passing through two inner link plates 1, two outer link plates 2 and the bushing 4, so as to joint the inner and the outer link plates 1, 2 together.
However, when the chain is used in different applications, it always needs to change the number of link plates for varying the length of the chain. Therefore, for separating the link plates, the pin 3 for jointing should be punched out of the inner and the outer link plates 1, 2, and after the unneeded link plates are removed, the now adjacent link plates are connected with connecting plates 6 whose shape is similar to the outer link plate 2, so that the pin 3 can again pass through the connecting plates 6, the inner link plates 1 and the bushing 4 for fixing. Then, after the end portion of the pin 3 is riveted, the length changing process can be completed.
Conventionally, when disassembling the pin 3, an acicular object is always utilized to remove the pin 3, in which both the pin 3 and the outer link plates 2 would be punched and damaged, so that not only the cost for altering the length is increased but the operation also is difficult.